Light-scattering dust sensor

Abstract

A light-scattering dust sensor includes: a light scattering region; a light emitter configured to emit light to the light scattering region; a light receiver configured to receive scattered light generated in the light scattering region; and an emitted light limiter located between the light emitter and the light scattering region, wherein the light emitted by the light emitter includes: peripheral light; and central light having an intensity that is more uniform than an intensity of the peripheral light, wherein the emitted light limiter is configured to block part of the emitted light, wherein the part of the emitted light blocked by the emitted light limiter includes the peripheral light.

What is claimed is: 
     
         1 . A light-scattering dust sensor comprising:
 a light scattering region:   a light emitter configured to emit light to the light scattering region;   a light receiver configured to receive scattered light generated in the light scattering region; and   an emitted light limiter located between the light emitter and the light scattering region,   wherein the light emitted by the light emitter comprises:   peripheral light; and   central light having an intensity that is more uniform than an intensity of the peripheral light,   wherein the emitted light limiter is configured to block part of the emitted light,   wherein the part of the emitted light blocked by the emitted light limiter comprises the peripheral light.   
     
     
         2 . The light-scattering dust sensor of  claim 1 , wherein the emitted light limiter comprises a slit or an aperture. 
     
     
         3 . The light-scattering dust sensor of  claim 2 , wherein the slit or the aperture has a size equal to or less than a width of the central light. 
     
     
         4 . The light-scattering dust sensor of  claim 3 , wherein the light emitter comprises a light-emitting diode (LED). 
     
     
         5 . The light-scattering dust sensor of  claim 4 , wherein the width of the central light is equal to or less than a width of light determined by a half angle of the LED. 
     
     
         6 . The light-scattering dust sensor of  claim 1 , further comprising a scattered light limiter located between the light receiver and the light scattering region,
 wherein the scattered light limiter is configured to block part of the scattered light, and   the light receiver is further configured to detect another part of the scattered light.   
     
     
         7 . The light-scattering dust sensor of  claim 6 , wherein the scattered light limiter comprises a plurality of hole structures sequentially arranged from the light scattering region to the light receiver,
 wherein the plurality of hole structures respectively comprise a plurality of holes having different sizes.   
     
     
         8 . The light-scattering dust sensor of  claim 7 , wherein, from among the plurality of holes, a hole adjacent to the light receiver is smaller than a hole adjacent to the light scattering region. 
     
     
         9 . The light-scattering dust sensor of  claim 8 , wherein the plurality of holes are three holes. 
     
     
         10 . The light-scattering dust sensor of  claim 9 , further comprising a scattered light focusing lens located between the scattered light limiter and the light scattering region,
 wherein the scattered light focusing lens is configured to focus the scattered light such that the focused light is provided to the receiver.   
     
     
         11 . The light-scattering dust sensor of  claim 10 , further comprising a heater configured to generate heat and thereby move dust particles.